<template>
    <div class="spec-preview">
        <img :src="skuImageList[defaultImg]?.imgUrl" />
        <div class="event" @mousemove="move"></div>
        <div class="big">
            <img :src="skuImageList[defaultImg]?.imgUrl" ref="bigImg" />
        </div>
        <div class="mask" ref="mask"></div>
    </div>
</template>

<script>
import { mapGetters } from "vuex";

export default {
    name: "Zoom",
    data() {
        return {
            defaultImg: 0, // 默认显示的图片
        };
    },
    computed: {
        ...mapGetters("details", ["skuImageList"]),
    },
    mounted() {
        // 图片列表切换
        this.$bus.$on("changeImg", index => {
            this.defaultImg = index;
        });
    },
    methods: {
        // 放大镜
        move(e) {
            let mouseX = e.offsetX;
            let mouseY = e.offsetY;
            let mask = this.$refs.mask;
            let bigImg = this.$refs.bigImg;
            let maskX = mouseX - mask.offsetWidth / 2;
            let maskY = mouseY - mask.offsetHeight / 2;
            if (maskX <= 0) {
                maskX = 0;
            } else if (maskX >= mask.offsetWidth) {
                maskX = mask.offsetWidth;
            }
            if (maskY <= 0) {
                maskY = 0;
            } else if (maskY >= mask.offsetHeight) {
                maskY = mask.offsetHeight;
            }
            mask.style.left = maskX + "px";
            mask.style.top = maskY + "px";
            bigImg.style.left = -2 * maskX + "px";
            bigImg.style.top = -2 * maskY + "px";
        },
    },
};
</script>

<style lang="less">
.spec-preview {
    position: relative;
    width: 400px;
    height: 400px;
    border: 1px solid #ccc;

    img {
        width: 100%;
        height: 100%;
    }

    .event {
        width: 100%;
        height: 100%;
        position: absolute;
        top: 0;
        left: 0;
        z-index: 998;
    }

    .mask {
        width: 50%;
        height: 50%;
        background-color: rgba(0, 255, 0, 0.3);
        position: absolute;
        left: 0;
        top: 0;
        display: none;
    }

    .big {
        width: 100%;
        height: 100%;
        position: absolute;
        top: -1px;
        left: 100%;
        border: 1px solid #aaa;
        overflow: hidden;
        z-index: 998;
        display: none;
        background: white;

        img {
            width: 200%;
            max-width: 200%;
            height: 200%;
            position: absolute;
            left: 0;
            top: 0;
        }
    }

    .event:hover ~ .mask,
    .event:hover ~ .big {
        display: block;
    }
}
</style>
